Commit a2216e18 authored by David Yang's avatar David Yang Committed by Herbert Xu
Browse files

crypto: hisilicon/trng - add support for HiSTB TRNG 



HiSTB TRNG are found on some HiSilicon STB SoCs.

Signed-off-by: default avatarDavid Yang <mmyangfl@gmail.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent e93c6085

drivers/crypto/hisilicon/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -82,3 +82,10 @@ config CRYPTO_DEV_HISI_TRNG 
	select CRYPTO_RNG

	help

	  Support for HiSilicon TRNG Driver.



config CRYPTO_DEV_HISTB_TRNG

	tristate "Support for HiSTB TRNG Driver"

	depends on ARCH_HISI || COMPILE_TEST

	select HW_RANDOM

	help

	  Support for HiSTB TRNG Driver.

drivers/crypto/hisilicon/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -5,4 +5,4 @@ obj-$(CONFIG_CRYPTO_DEV_HISI_SEC2) += sec2/ 
obj-$(CONFIG_CRYPTO_DEV_HISI_QM) += hisi_qm.o

hisi_qm-objs = qm.o sgl.o debugfs.o

obj-$(CONFIG_CRYPTO_DEV_HISI_ZIP) += zip/

obj-$(CONFIG_CRYPTO_DEV_HISI_TRNG) += trng/
 
obj-y += trng/

drivers/crypto/hisilicon/trng/Makefile

+3 −0
Original line number Diff line number Diff line 
obj-$(CONFIG_CRYPTO_DEV_HISI_TRNG) += hisi-trng-v2.o

hisi-trng-v2-objs = trng.o



obj-$(CONFIG_CRYPTO_DEV_HISTB_TRNG) += histb-trng.o

histb-trng-objs += trng-stb.o

drivers/crypto/hisilicon/trng/trng-stb.c

0 → 100644
+176 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later OR MIT

/*

 * Device driver for True RNG in HiSTB SoCs

 *

 * Copyright (c) 2023 David Yang

 */



#include <crypto/internal/rng.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/hw_random.h>

#include <linux/io.h>

#include <linux/iopoll.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of_device.h>



#define HISTB_TRNG_CTRL		0x0

#define  RNG_SOURCE			GENMASK(1, 0)

#define  DROP_ENABLE			BIT(5)

#define  POST_PROCESS_ENABLE		BIT(7)

#define  POST_PROCESS_DEPTH		GENMASK(15, 8)

#define HISTB_TRNG_NUMBER	0x4

#define HISTB_TRNG_STAT		0x8

#define  DATA_COUNT			GENMASK(2, 0)	/* max 4 */



struct histb_trng_priv {

	struct hwrng rng;

	void __iomem *base;

};



/*

 * Observed:

 * depth = 1 -> ~1ms

 * depth = 255 -> ~16ms

 */

static int histb_trng_wait(void __iomem *base)

{

	u32 val;



	return readl_relaxed_poll_timeout(base + HISTB_TRNG_STAT, val,

					  val & DATA_COUNT, 1000, 30 * 1000);

}



static void histb_trng_init(void __iomem *base, unsigned int depth)

{

	u32 val;



	val = readl_relaxed(base + HISTB_TRNG_CTRL);



	val &= ~RNG_SOURCE;

	val |= 2;



	val &= ~POST_PROCESS_DEPTH;

	val |= min(depth, 0xffu) << 8;



	val |= POST_PROCESS_ENABLE;

	val |= DROP_ENABLE;



	writel_relaxed(val, base + HISTB_TRNG_CTRL);

}



static int histb_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)

{

	struct histb_trng_priv *priv = container_of(rng, typeof(*priv), rng);

	void __iomem *base = priv->base;



	for (int i = 0; i < max; i += sizeof(u32)) {

		if (!(readl_relaxed(base + HISTB_TRNG_STAT) & DATA_COUNT)) {

			if (!wait)

				return i;

			if (histb_trng_wait(base)) {

				pr_err("failed to generate random number, generated %d\n",

				       i);

				return i ? i : -ETIMEDOUT;

			}

		}

		*(u32 *) (data + i) = readl_relaxed(base + HISTB_TRNG_NUMBER);

	}



	return max;

}



static unsigned int histb_trng_get_depth(void __iomem *base)

{

	return (readl_relaxed(base + HISTB_TRNG_CTRL) & POST_PROCESS_DEPTH) >> 8;

}



static ssize_t

depth_show(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct histb_trng_priv *priv = dev_get_drvdata(dev);

	void __iomem *base = priv->base;



	return sprintf(buf, "%d\n", histb_trng_get_depth(base));

}



static ssize_t

depth_store(struct device *dev, struct device_attribute *attr,

	    const char *buf, size_t count)

{

	struct histb_trng_priv *priv = dev_get_drvdata(dev);

	void __iomem *base = priv->base;

	unsigned int depth;



	if (kstrtouint(buf, 0, &depth))

		return -ERANGE;



	histb_trng_init(base, depth);

	return count;

}



static DEVICE_ATTR_RW(depth);



static struct attribute *histb_trng_attrs[] = {

	&dev_attr_depth.attr,

	NULL,

};



ATTRIBUTE_GROUPS(histb_trng);



static int histb_trng_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct histb_trng_priv *priv;

	void __iomem *base;

	int ret;



	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	base = devm_platform_ioremap_resource(pdev, 0);

	if (IS_ERR(base))

		return -ENOMEM;



	histb_trng_init(base, 144);

	if (histb_trng_wait(base)) {

		dev_err(dev, "cannot bring up device\n");

		return -ENODEV;

	}



	priv->base = base;

	priv->rng.name = pdev->name;

	priv->rng.read = histb_trng_read;

	ret = devm_hwrng_register(dev, &priv->rng);

	if (ret) {

		dev_err(dev, "failed to register hwrng: %d\n", ret);

		return ret;

	}



	platform_set_drvdata(pdev, priv);

	dev_set_drvdata(dev, priv);

	return 0;

}



static const struct of_device_id histb_trng_of_match[] = {

	{ .compatible = "hisilicon,histb-trng", },

	{ }

};



static struct platform_driver histb_trng_driver = {

	.probe = histb_trng_probe,

	.driver = {

		.name = "histb-trng",

		.of_match_table = histb_trng_of_match,

		.dev_groups = histb_trng_groups,

	},

};



module_platform_driver(histb_trng_driver);



MODULE_DESCRIPTION("HiSTB True RNG");

MODULE_LICENSE("Dual MIT/GPL");

MODULE_AUTHOR("David Yang <mmyangfl@gmail.com>");